Blanket clamping assemblies for web offset rotary printing presses, or letter presses



April 18, 1961 H. J. LUEHRS BLANKET CLAMPING ASSEMBLIES FOR WEB OFF Filed July 16, 1959 SET ROTARY PRINTING PRESSES. 0R LETTER PRESSES 3 Sheets-Sheet 1 w m: H]

i 5 WW F '1 i E E i N Q E "W i m I INVENTOR 4 ATTORNEYS BLANKET CLAMPING ASSEMBLIES FOR WEB OFF SET ROTARY PRINTING PRESSES. 0R LETTER PRESSES Filed July 16, 1959 3 Sheets-Sheet 2 April 1961 H. J. LUEHRS 2,980,016

HANG J.LUEHRS W ATTORNEYS April 18, 1961 H. J. LUEHRS 2,980,016

BLANKET CLAMPING ASSEMBLIES FOR WEB OFF SET ROTARY PRINTING PRESSES. 0R LETTER PRESSES Filed July 16, 1959 a Sheets-Sheet 5 9 T mm INVENTOR HANS J LUE H RS BY aw @Z ATTORNEYS United States Patent;

BLANKET CLAMPING ASSEMBLIES FOR WEB OFFSET' ROTARY PRINTING PRESSES, OR LETTER PRESSES Hans J. Luehrs, Westerly, R.I., assignor to The Cottrell This invention is directed to improvements in blanket clamping assemblies for web ofiset rotary, printing presses, or letter presses.

An object of this invention is to provide the rotary blanket cylinder with a bore having a narrow slot along the peripheral surface of the cylinder, said bore serving to house the blanket clamping assembly, and said slot serving to receive therethrough the head and tail ends of the said blanket, the bore and slot being parallel to the cylinder axis. A further object is to provide a novel blanket assembly which includes coacting devices for registering and clamping the head and tail ends of the blanket and, also, tensioning on the tail end, for ensuring a' close fit of the blanket on the cylinder. 1 V

A further object is to provide a clamping assembly which includes a rotatable shaft and a split tube substantially encircling said shaft throughout its length and located in said cylinder bore, which shaft is provided with a device for clamping the head end of the blanket and another device for clamping the tail end of the blanket to tension same on the cylinder. A practical embodiment of this invention is shown in the accompanying drawing in which, Fig. 1 represents a plan view of an offset blanketcylinder with an intermediate portion broken away,

Fig. 2 represents an end view of the cylinder,

Fig. 3 represents an enlarged detail section taken in the plane of line III-III of Fig. 1 looking in the direction of the arrows, with the blanket clamp in one position,

Fig. 4 represents a similar section with the blanket clamp in a second position, showing both blanket 'ends stopped and registered.

Fig. 5 represents a similar section with the blanket clamp in a third and tensioned position, said Figs. 3, 4 and 5 illustrating the application of the blanket to the cylinder,

Fig. 6 represents a detail section taken in the planes 2 of line VIVI of Fig. 3, looking in the direction of the arrows.

Fig. 7 represents a detail section taken in the plane of line VIIVII of Fig. 3,

Fig. 8 represents a detail section taken in the plane of line VIIV1I of Fig. 5 looking in the direction of the arrows; and

Fig. 9 represents an enlarged detail section taken in the planes of lines 9-9 of Fig. 2, looking in the direction of the arrows.

The rotary blanket cylinder 1 is shown as having a narrow slot 2 along its peripheral surface for receiving the head and tail ends of the blanket 4, which slot 2 opens into a bore 3 located in the cylinder 1 adjacent its peripheral surface. The slot 2 and bore 3 are shown as parallel to the axis of the cylinder 1.

A shaft 5 is located in the cylinder bore 3 and is rotatably mounted at the ends of the cylinder in suitable bearings 6. The means for turning the shaft in either .mitting the'tail end of the slot into bore '3 until the tail end is stopped an Patented A r. 1 1961 direction is shown as comprising a-gear 7 carried on a sleeve 8 keyed to the end of the shaft 5, which gear meshes with a worm 9 rotatably mounted in a casing 10 at the end of the cylinder, which worm may be turned by a suitable tool, such as a socket wrench (not shown). The shaft 5 is provided along one side thereof with a backup piece 11 and along the'opposite side with a key '12, which are both shown as secured to the shaft by screws 13 A split tube preferably of highly tempered material partly surrounds the shaft 5 and is secured thereto and spaced therefrom by said key 12. This tube comprises a thick rigid portion 14 upon one side of the key 12 in contact with the wall of the bore 3 and a flexible portion 15 upon the other side of the key, spaced both from the shaft 5 and the wall of the bore, and urged toward said wall to assist in clamping the blanket.

Inwardly directed blanket engaging pins 16 are carried by the cylinder 1 which pins project within circumferential grooves 17 in the rigid portion 14 of the tube in position to engage the head end of the blanket 4, when the said rigid portion 14 of the tube has been moved therefrom by the turning of the shaft 5. Outwardly directed pins 18 are carried by the spring portion 15 of the split tube.- Springs 19 carried by the shaft 5 serve to urge the flexible portion'15 to cause these pins 18 to engage the tail end of the blanket 4 when brought in contact therewith by the turning of the shaft during operation.

The shaft 5 with its clamping devices is turned counter clockwise to the position shown in Fig. 3. The head end of the blanket 4 is then inserted through the slot into the groove formed between the shaft 5 and the rigid portion 14 of the split tube, until the front end of the blanket is stopped and registered by the key 12. The shaft 5 is then turnedagain counter clockwise to the position shown in Fig. 4 to cause the head end of the blanket to be engaged between the backup piece 11 and wall of the cylinder bore, causing the impaling pins 16 to engage the head end of the blanket; and also perthe blanket to be inserted through contact with the backup piece 11. g 5 is then turned further counterclockwise, Soto cause the tail end of the blanket to registered by The shaft tact with the head end of the blanket and clamped. This operation will pull the tail end under tension tightly around the cylinder, as well as exerting additional clamping pressure against both blanket ends.

It has been found that blankets must be highly tensioned to perform satisfactorily. Thus, the construction of the blankets consists of a thick strong rubberized woven webbing to resist stretch and a thin smooth top layer of rubber for successful printing. As shown, the pins 16 and 18 will only engage the woven webbing or the strongest side of the blanket to assure a perfect nonslipping clamping action. The smooth rubber surfaces will permit easy relative motion between blanket ends for the clamping and takeup operation.

It will be noted that the extreme lead end of the blanket 4 always remains in'the grooves 17 between the shaft 5 and the tube surrounding same while the blanket is clamped and tensioned around the cylinder. A minimum portion of this lead end of the blanket must remain in these grooves to facilitate removal of the blanket as'de'scribed below.

For the removal operation the shaft 5 and its edge are rotated in clockwise direction. As tension is removed from the blanket clamping pressure will be correspondingly reduced so that the withdrawal of the tail end upon further clockwise rotation of shaft 5 may be accomplished. Simultaneously the lead end of the blanket will have been further entered into the groove and continuing the rotation of shaft 5 the knife edge of the flexible edge as shown in Fig. 5 will engage thelead end of the blanket and peel it from the pins 16 so that this end of theblanket also may be withdrawn.

It will be seen that the clamping assembly shown and described permits the use of a very narrow slot in the cylinder and also eliminates all filling in pieces in the cylinder, and provides a positively acting holding means for the blanket ends combining increased clamping pressure and pin point punctures. This assembly also eliminates reinforcements or special construction of the blanket ends. 7 I

Since it is evident that various changes may be made in the form, construction and arrangements of the several parts, I do not intend to be limited to the embodiments herein shown and described except as set forth in the appended claims.

What I claim is:

1. A blanket clamping assembly for web rotary printing presses comprising the combination with a rotary cylinder having a narrow slot located along its peripheral surface and opening into a longitudinal bore located in the cylinder near its peripheral surface of a blanket, said slot and bore being adapted to receive the blanket ends, a manually rotatable shaft mounted in said bore, a split tube partly surrounding and spaced from said shaft and secured thereto, and coacting devices carried by said shaft, split tube and cylinder for pinning clamping and tensioning the blanket to the cylinder as the shaft is turned in one direction.

2. A blanket clamping assembly according to claim '1, in which the said coacting devices include elements secured to said shaft along its opposite sides for registering both ends of said blanket, and other elements in the cylinder bore opposed to part of the first named elements for fixedly holding the blanket end in its clamped position.

3. A blanket clamping assembly according to claim 1, in which the split tube is provided with a spring biased flexible portion for moving the devices carried thereby toward their coacting devices on the cylinder, whereby the blanket is penetrated and held by said movable and fixed devices.

4. A blanket clamping assembly according to claim 1, in which the coacting devices on the split tube are adapted to be flexed toward the devices in the cylinder to a degree in proportion to the tension applied to the blanket as it is being clamped to the cylinder.

5. A blanket clamping assembly according to claim 1, in which the split tube is divided into a spring biased flexible portion carrying some of said coacting devices and a rigid portion, and in which the shaft is provided with a key, and means for securing the key and split tube to the shaft.

6. A blanket clamping assembly comprising arotary cylinder having a blanket end receiving narrow slot located along its peripheral surface and opening into a bore adjacent said peripheral surface, a manually rotatable shaft in said bore, a split tube partly surrounding the shaft substantially throughout its length and spaced therefrom, a back up piece and a key piece on the shaft, means for securing the split tube, the backup piece and the key piece to said shaft, said split tube including a rigid portion contacting the bore wall and a spring biased yielding portion, impaling pins in the cylinder bore wall for coaction with the back up piece when the shaft is turned for fixedly securing one end of the blanket and impaling pins carried by the yielding portion of the split tube for engaging and securing the other end of the blanket, under tension, when said shaft is further turned.

7. In a rotary printing press the combination including a blanket cylinder and a blanket therefor, a longitudinal bore across said cylinder, said bore terminating in a narrow slot in the periphery of the cylinder for receiving both ends of said blanket, a rotatable shaft mounted in said bore, a split tube partly surrounding and spaced from the shaft and secured thereto and means for clamping and tensioning said blanket to the cylinder, comprising inwardly directed elements carried by the cylinder for penetrating one end of the blanket, and coacting outwardly directed movable elements carried by said split tube for penetrating the other end of said blanket.

References Cited in the file of this patent UNITED STATES PATENTS 2,164,480 Tornberg July 4, 1939 2,186,764 Meisel Jan. 9, 1940 2,279,204 Neilson Apr. 7, 1942 2,621,592 Faeber Dec. 16, 1952 FOREIGN PATENTS 368,987 Great Britain Mar. 17, 1932 607,498 Great Britain Sept. 1, 1948 

